This application relates to and claims a priority from corresponding Japanese Patent Application No. 2001-212245 filed on Jul. 12, 2001.
1. Field of the Invention
The present invention relates to a break roll machine for breaking such grains as wheat grains, and more particularly to a break roll machine in which the replacement of the rolls can be performed with ease.
2. Description of the Related Art
As a break roll machine which is used in a flour milling plant, a multiple roll machine, as shown in FIG. 5, in which two sets of a pair of rolls 102, 103 are arranged in a machine frame 101 is well known in the art. The multiple break roll machine 100 is divided into two by a center partition board 104 so that two sets of the pair of rolls 102, 103 operate independently with each other. For example, the machine illustrated in FIG. 5 is divided into two parts, one being the coarse roll side 107 at which the operation of breaking and developing of the stock of raw materials is performed and the other one being the smooth roll side 108 at which the frictional breaking of the stock is performed. Further, the break roll machine 100 is provided with a differential transmission mechanism 109 (see the coarse roll side 107) for causing the pair of rolls 102 and 103 to rotate respectively inwardly at the different peripheral speeds. The roll machine 100 is also provided with a roll gap adjusting mechanism 110 for adjusting a nip or gap defined between the pair of rolls 102 and 103.
In the break roll machine 100 as described above, with the lapse of time, there develops wear of the coarse rolls, the surface of the smooth rolls becomes rough, the rolls lose their roundness, and the pear surface of the rolls becomes too smooth due to the wear. Therefore, the surfaces of the rolls 102 and 103 are required to be coarse or grinded or polished. In performing the maintenance, it is effective that the used rolls are replaced by the spare rolls sequentially according to a predetermined schedule. Although the appropriate timings of the roll replacement depend on such conditions as the locations of the rolls, the materials of rolls, kinds of raw materials, the tightening degree of the rolls, and the degree of load, span of period may be between four months to one year for the coarse rolls and between six months to two years for the smooth rolls.
Hereunder, actual operation for replacement of the rolls is explained. When the pair of rolls 102 and 103 are to be removed from the machine frame 101, it is necessary that the drive-transmission means such as belts be first removed or disassembled from the main drive means. The drive-transmission means includes, for example, a V-belt (not shown) and V-belt pulleys which connect between a drive motor (not shown either) as the drive source and the rolls (102 and/or 103). Since such V-belt pulleys are generally mounted on the end portions of the motor drive shaft and the roll driven shaft and the width of the V-belt is small, possibility of interference of these components with other components or their projection portions is small. As a result these components can be easily removed or disassembled by simply loosening the tension applied thereto.
On the other hand, a timing belt 111 of the differential transmission mechanism 109 shown in FIG. 5 has a wide width configuration, the removal or disassembling of the same is fairly difficult. The differential transmission mechanism 109 is constituted by timing-belt pulleys 112, 113 respectively mounted on the rolls 102, 103; an idler pulley 114; the timing belt 111 of the wide width configuration wound on the timing-belt pulleys 112, 113 and the idler pulley 114; a tension arm 115 on which the rotary axis of the idler pulley 114 is received; and a tension mechanism 116 which applies an appropriate tension to the timing belt 111 based on the rotation of the same. Where the timing belt 111 wound on the timing-belt pulleys 112, 113 and the idler pulley 115 is to be removed, a rod 116a is contracted by the operation of the tension mechanism 116 so that the tension arm 115 is pivotally rotated in the direction of left, namely, in the arrow direction in the drawings. In this way, the timing belt 111 is loosened. Next, since the pivot 115a of the tension arm 115 is secured to the lower portion 104a of the center partition board 104 by bolts, these bolts are removed and, then, the tension arm 115 itself is removed from the machine frame 101. Thereafter, the timing-belt 111 of the wide width configuration is removed from the timing-belt pulleys 112, 113 and the idler pulley 114.
After the removal of the drive-transmission means such as the V-belt and timing belts from the main drive means, the pair of rolls 102, 103 are removed from the machine frame 101. However, between the rolls 102, 102 and the machine frame 101, there is further connected a roll gap adjusting mechanism 110. The Japanese Patent Application Kokai-Publication No. Hei 8-206,522 discloses a roll pack of the pre-assembled module construction as shown in FIG. 6 in which the rolls 102 and 103 are mounted in advance in a movable bearing housing 117 and a fixed bearing housing 118, respectively. In this case, by disconnecting the circular-coupling between an arm rod 120 of the roll gap adjusting mechanism 110 and an air cylinder 121 and, further, by removing the fastening bolts 122, 123 and 124, the pre-assembled roll pack module 119 can be removed from the main frame 101 in a short time and new one can be installed in a short time with ease.
However, among the bolts for firmly fixing the roll pack module 119 to the machine frame 101, there is a bolt 124 (see FIG. 6), for example, which is located behind the air cylinder 121 and to which it is difficult to access to head portion of the bolt by tools such as a spanner and a box wrench because the air cylinder 121 interferes with such tools. To cope with this problem, in order to remove the fastening bolt 124, it has been necessary that the air cylinder 121 is inclined left or right (as shown in two-dotted line in FIG. 6), or the air cylinder itself is once removed entirely from the machine frame 101.
Further, as shown in FIG. 5, when the wide width timing-belt 111 is to be removed from the pulleys 112, 113 and the idler pulley 114, the tension arm 115 itself should be removed from the machine frame 101. In this case, since the number of the bolts to be removed is large, there has been a problem that such operation is troublesome and time-consuming.
One object of the present invention is to over-come the above explained problems in the prior art.
Another object of the present invention is to provide a break roll machine in which a timing belt of a differential transmission mechanism can be removed easily, a pre-assembled roll pack module can be removed from a machine frame in a short time and a new roll pack module can be reinstalled in a short time with ease.
According to one aspect of the invention, there is provided a break roll machine having: a fixed roll bearing housing fixed to a machine frame; a movable roll bearing housing which is movable nearer or further with respect to the fixed roll bearing housing; a pair of break rolls rotatably held by the fixed roll bearing housing and the movable roll bearing housing, respectively; a roll gap adjusting mechanism provided between the fixed roll bearing housing and the movable roll bearing housing, for adjusting a gap defined between the pair of break rolls; and a differential transmission mechanism for causing the pair of break rolls to rotate respectively inwardly at different circumferential speeds with each other, the differential transmission mechanism characterized by comprising:
timing-belt pulleys mounted to rotary shafts of the pair of break rolls, respectively;
a timing belt wound on the timing-belt pulleys;
an idler pulley for applying a predetermined tension to the timing belt;
a pair of tension arms which sandwich the idler pulley therebetween and rotatably hold a rotary shaft of the idler pulley at first end portions, and which are mounted rotatably at second end portions, one of the paired tension arms located at an opposite side of the break rolls having at the first end portion a cutout portion which can release the rotary shaft of the idler pulley;
an operation lever for causing the first end portions of the paired tension arms together with the idler pulley to rotate around a pivot point at the second end portions of the tension arms; and a tension adjusting mechanism which moves the operation lever for adjusting a position of the idler pulley.
In the break roll machine as constructed above, when the bolt which pivotally secures the tension arm to the machine frame is removed, the rotary shaft of the idler pulley is released from the fastening state and only the tension arm becomes rotatable around the pivot point of the one end of the tension arm as the center. That is, without the necessity of removing the tension arm entirely from the machine frame and only by removing the minimum number of the bolts, the timing belt of the wide width configuration can be removed without difficulty.
The roll gap adjusting mechanism comprises a connecting rod for connecting the fixed roil bearing housing and the movable roll bearing housing over the pair of break rolls, a lever pivotally and eccentrically mounted to one end portion of the connecting rod, an air cylinder coupled to an outside end portion of the lever through a first coupling means, and a piston of the air cylinder. The first coupling means between the piston and the lever is constituted by an R-pin and a bush.
In this way, since the bush member can be easily pulled out after the R-pin is pulled out by fingers of the operator, the lever and the piston can be easily drawn out.
Further, there is provided a break roll machine in which the second coupling means between the lower end portion of the air cylinder and the machine frame is constituted by a first linkage member which is rotatable to move backward and forward and a second linkage member which is rotatable to move left and right. In this way, the air cylinder becomes possible to be rotated freely in the backward and forward direction and/or in the left and right direction. For example, if the air cylinder is caused to be inclined in the direction of backward or forward, the bolt located behind the air cylinder is exposed so that an access thereto for an operator from the front side becomes available. In this case, as such tool as a spanner or a box wrench can be inserted to the bolt from the front side without being interfered by the air cylinder, such tool can be inserted to the head of the bolt without difficulty. Accordingly, since there is no necessity of such troublesome operation as removing the air cylinder from the machine frame in removing the fastening bolt, it is possible to remove the pre-assembled roll pack module in a short time and to reinstall the new roll pack module with ease and also in a short time.